Nick Morgan (Letters, 21 June) praising Bob Dylan's songs to Paul McCartney's disadvantage is deeply wrong-headed. He writes as though the lyrics were the most significant aspect of a song. In that respect alone most critics and listeners would agree that Dylan has the edge. But Bob's melodies are not a patch on Paul's best, whether judged on invention or originality. A simple test: compare the number of instrumental cover versions each composer has to his credit. Paul's tunes lend themselves to countless reinterpretations in many varying musical styles. The same cannot be said for Dylan's.Tony CashLondon

• Am saving to buy the grandchildren a couple of Conway Stewarts, anticipating any day now an announcement that Mr Gove expects every child to own and use a fountain pen (Letters, 22 June).John BaileySt Albans, Hertfordshire

• Thank you and Garry Trudeau for bringing us Doonesbury: the Leo/Alex relationship has been a simultaneously lovely and amusing story and, yet again, his strip today (21 June) made me smile, then wipe away a tear. The man is a genius.Chris FairchildScarborough, North Yorkshire

• I have noticed that the people appearing in television commercials are getting fatter. Is this being done as a sop to our overweight population and to help them feel more favourably towards the products being promoted (TV highlights, The Men Who Made Us Fat, 21 June)?Louis PlattKnebworth, Hertfordshire

• Re the inadequacy of the Turing test of artificial intelligence (Letters, 22 June): of course computers will never fully understand flowing, allusive conversation. But they won't care.Brian Reffin SmithBerlin

• In my youth I often made salad cream sandwiches liberally topped with sugar (Letters, 20 June), and especially when Wimbledon tennis was on TV. Which reminds me (Wimbledon Countdown, 20 June), better stock up on bottles.Roger WalkerBradford